Gastric Focused Ultrasound Stimulation

Inclusion Criteria: * Age 18 to 70 years. * Delayed gastric emptying or gastroparesis diagnosed by a clinician and confirmed by gastric emptying scintigraphy or a gastric emptying breath test. * Ability to understand the study procedures, provide informed consent, and complete two study visits. * Ability to consume the two bottles of Ensure or Glucerna nutritional drink used in the study. Exclusion Criteria: * Pregnancy. * Epilepsy. * Cardiac pacemaker or another implanted electronic medical device. * Peritoneal dialysis. * Daily use of narcotic or opioid medications. * Abdominal wall ulcers, open wounds, active infection, or significant skin irritation in the area where the electrogastrography electrodes or focused ultrasound transducer will be placed. * Known allergy or contraindication to the available Ensure or Glucerna nutritional drinks. * Any other medical or safety condition that, in the judgment of the study team, would make participation unsafe. Medication Restrictions: Participants using medications that may significantly affect gastric motility or gastric emptying may be rescheduled if those medications were used within the study-defined restriction period. Relevant medications include opioid analgesics, prokinetic agents, anticholinergic or antispasmodic agents, GLP-1 receptor agonists or related medications, and anti-nausea or antiemetic medications that may affect gastrointestinal function. Participants should not discontinue any medically necessary medication without first consulting their treating physician.